What is a Supernova – Definition & Facts of Star Explosion in Space – PlanetFacts.org Supernova What is a Supernova? To say in three words, a supernova is an exploding star. Okay, that was more than three, but you get the point. A supernova is more significant than a nova, but less so than a hypernova. Supernovae are very bright and generate bursts of radiation that can briefly outshine a whole galaxy before declining in brightness over many weeks or months. In this period a supernova can emit as much energy as the Sun might over its entire lifetime. How Supernovae are Studied By using optical telescopes, astronomers can approximate the amount of light generated by a supernova. These measurements can be used to determine how the luminosity and color of a supernova vary with time. Astronomers may examine the light through a prism, which breaks the light from a supernova into the spectrum of colors that composes it. From this, astronomers can gauge how the brightness of light depends on that light’s wavelength. The luminosity could change at all wavelengths. The spectrum of a supernova can very with time as well, until it fades entirely of course.

The study of a supernova is more than just a study of any ordinary light show. Both the light and spectrum of color of a supernova can be used to make conclusions about the physics that occurs during and after supernova explosions. Understanding how a supernova explosion occurs and progresses is crucial to understanding why certain stars go boom. Supernovae are responsible for producing and dispersing elements into the interstellar medium. The elements that form stars, planets, and life on Earth are created and spread by supernovae. You could say that we are made of stardust. Naming Convention Supernovae are reported to the International Astronomical Union’s Central Bureau for Astronomical Telegrams, which assign them a name. The name begins with “SN”, the prefix for supernova, followed by the year, followed by a string of letter from A to Z. The first 26 supernovae are attached with a capital letter (A-Z). Following this are pairs of lower-case letters, such as aa, ab, ac, so on and so forth. For example the 367th supernova discovered in 2005 would be named SN 2005 nc.

This naming convention was utilized since 1885. However, up until 1947, rarely would more than one supernova was found per year. Two-letter designations were scarcely necessary until 1987, and since 1988, they have been necessary more and more every year. Supernovae Types Since 1941, Rudolf Minkowski discovered that some spectra contain hydrogen and some do not, and therefore supernovae are classified by Type I, ones lacking hydrogen in their spectra, and Type II, ones that strongly show strong hydrogen lines. Since 1985, Type I supernovae have been classified further. Type Ia supernovae have a silicon spectral line at 615 nm, and Type Ib does not. Type Ib supernovae have strong helium lines, and Type Ic do not. Type I supernovae are classified such because of the sharp maxima and smooth decay of light in their light curves. The initiation of a Type I supernova can be modeled as an explosion of a carbon white dwarf that is crushed under the pressure of electron degeneracy.

Supernovae Models The assumption follows that a white dwarf accumulates enough mass that it exceeds the Chandrasekhar limit of 1.4 solar masses (for white dwarves, this is the mass at which the star’s core can no longer resist gravitational collapse). The core temperature of the white dwarf rises dramatically, setting off chains of nuclear fusion reactions that essentially blow the star up. This model is consistent with the fact that Type I supernovae are hydrogen deficient, since white dwarves contain nearly zero hydrogen. Furthermore, the slow decay of light is consistent with the model, because the radioactive decay of unstable heavy elements produced by the supernova produces most of the energy. Supernovae of Type I can be further categorized into Types Ia, Ib, and Ic. Type Ia supernovae are indicated by the lack of hydrogen and have an observable ionized silicon line at 615.0 nm. Type Ib supernovae have a non-ionized helium line at 587.6 nm and no silicon absorption feature at 615.0 nm. Type Ic supernovae have feint or no helium lines as well as no silicon absorption features near 615.0 nm.

Sometimes Types Ib and Ic supernovae are hard to distinguish between because they are so similar, so astronomers may indicate “Type Ibc” to avoid the trouble of precise naming. Type II supernovae are modeled after massive stars that explode and/or implode. A plateau is apparent in their light curves a few months after initiation. The explanation for the plateau is that energy is generated by the heating and cooling of the star’s outer layer as it is carried into space. The observation of the strong hydrogen and helium spectra confirms this, as there should be a large amount of these gaseous elements on the outermost layers of the massive star. Type II supernovae can be further categorized based on their spectra. Type IIP depicts a plateauing in its light curve. Type IIL shows a linear decline in its light curve (magnitude vs. time). Furthermore, while most Type II supernovae depict wide emission lines that indicate velocity expansion at the scale of thousands of km/s, some possess relatively narrow lines. These are labeled as Type IIn (“n” as in “narrow”). Supernovae that are peculiar are notated with “pec”.

Some supernovae change types over the course of weeks and months, starting with hydrogen lines that get dominated by helium lines. The combination of features between Types II and Ib have contributed to the notation of these supernovae as Type IIb. Where Supernovae Occur Supernovae have been observed in galaxies across the entire Universe. There are three types of galaxies: ellipticals, spirals, irregulars. Type Ibc and II supernovae have been taking place in spiral and irregular galaxies, specifically in areas of these galaxies where massive stars have formed in the previous 10 million years or so. Since Type II has not been seen in elliptical galaxies, it is said that these supernovae occur with explosions of massive stars. Type Ia supernovae have been observed in all galaxy types, but generally not near massive star formations. Since few to no stars form in elliptical galaxies, it is said that Type Ia supernovae occur from stars that are older and less massive. Supernovae Theories: Death Star Theorists tend to notice that stars greater than 8 solar masses tend to explode, if they do, as Type II and Type Ibc supernovae.

These stars are relatively young and massive, which manifest in irregular or spiral galaxies. They also notice that Type Ia supernovae can be depicted by the explosion of low-mass stars called white dwarves. The study of how stars develop and evolve over time throughout their lives is important to understanding supernovae. A close examination of stars can be distinguished into an internal study and an external study, since two different events occur on the inside and outside of stars. Stars produce energy over the course of their lifecycle by the process known as nuclear fusion. Nuclear fusion is a process in which atomic nuclei (the proton/neutron cores of atoms) fuse to form new elements as well as release incredible amounts of energy. In stars, the nuclei of lighter elements like hydrogen and helium fuse, under extreme temperatures and pressures at the central core of stars, to produce nuclei of heavier elements. Note that electrons are in complete free flow from atomic nuclei under the extreme pressures and temperatures at the core of stars. Using the mass-energy principle that Albert Einstein discovered, E=mc2 (energy = mass times the square of the speed of light), we know that large masses of matter produce energy.

Nuclear fusions inside stars generate extreme amounts of energy that burst to the stellar exterior, some of which becomes the light that shines from stars. Photo by: Wikipedia Creative Commons In the core of massive stars greater than 8 solar masses, nuclear fusion results in a chain of element formations: from hydrogen to helium nuclei, to complicated reactions that eventually result in silicon nuclei, which ultimately form iron nuclei. An iron nucleus is the most stable naturally occurring element outside of supernovae explosions; it cannot be fused into heavier elements without incredibly large bursts of energy. Because of this, the core of massive stars slowly becomes a large chunk of iron nuclei. Once a star’s core is completely saturated with iron nuclei, nuclear fusions will cease, and the star’s energy production will come to an end. Without energy to support itself, the star will collapse: its core can no longer resist the force of its gravity. The star’s core and all the matter above the core will be crushed inward by gravity. Ultimately, only neutrons will survive the implosion of the star, and in the final act, the neutrons form a new core which becomes that which is known as a neutron star.

As the neutron core stabilizes, what is left of the previous massive star will flow in limbo. Once the core stops collapsing, like a super-compressed perfect spring, it bounces out and releases all of the compressed energy. This shockwave will burst and rip through the outer layers of the star. All that was the massive star extinguishes in an, excuse the pun, astronomical explosion, and only the new neutron star might survive the blast. Massive stars tend to die with a Type II or Type Ibc supernova. The entire supernova process occurs over a scale of a few milliseconds. Photo by: Wikipedia Creative Commons Sometimes a collapsing core of neutrons will become so massive that it never quite rebounds and will instead form an event horizon (the outer layer of a black hole in which not even light can escape) at the bottom of its collapse. The pressures built up never quite escape this event horizon, and there is no shockwave to start a supernova. Eventually the star remnants fall into the newly forming black hole. It is theorized that sometimes a supernova can result in a black hole formation, under certain conditions. The Sun will not die with a supernova.

This Sun will, at a slow pace, fuse its core hydrogen nuclei into helium nuclei over the next 5 billion years or so. Once its core becomes all helium, these will slowly fuse into carbon nuclei in a relatively short amount of time. The carbon nuclei in turn will not fuse into anything else because the Sun is not hot enough. The carbon core would no longer support the Sun and collapses under its own weight. Despite this, the blanket of free flow electrons in the Sun will resist total collapse. The Sun will become a white dwarf. What remains outside of the white dwarf get shrugged off to form a planetary nebula. As this nebula slowly spreads into space over thousands of years, the white dwarf of what was the Sun will continue to glow away what is left of its energy over the course of the next billions of years. This white dwarf will continue to exist until it reaches conditions for a Type 1a supernova, which is explained above under the “Supernovae Models” section. Supernovae Effects The explosion caused by a supernova has significant effects on the space surrounding it. The tremendous shockwave caused by a supernova can press and condense gas in the environment.

If the gas was quite dense to begin with, then the pressure exerted on it could collapse into the formation of new stars. A supernova explosion could create new elements, especially those heavier than iron. These new elements disperse into space and enrich surrounding gas mediums. In this way, stars formed after supernovae tend to have greater heavy element concentrations. In fact, it is this very enrichment of the gas in the Milky Way that has contributed to the rise of life on Earth! Supernovae may also send small proton, alpha (helium nuclei), and electron particles through space (these are all called cosmic rays or cosmic ray particles). It is said that the beaming of these high-energy, high-momentum particles on Earth contributed to genetic mutation, and therefore, biological evolution on Earth. Supernovae and the Fate of the Universe Supernovae of Type Ia are the brightest subjects in the Universe. They are used as signpost beacons of light that could be used to estimate distances in space. Astronomers are currently utilizing light from Type Ia supernovae to measure distances in nearby galaxies.

It is theorized that by measuring these distances along with the speeds at which these galaxies are moving away from us (due to the Universe constantly expanding), a serious study done by Edwin Hubble, we can measure how much matter is in the Universe as well as the Universe’s final fate. According to Einstein and the theory of general relativity, the amount of matter in the Universe contributes to what geometry it has. Einstein theorized that matter curves the space and time around it, and therefore the whole Universe. More matter means more curvature, more curvature means that the expansion of the Universe will halt due to gravitational force. If this occurs, then Universe will implode in a Big Crunch. On the other hand, if there is insufficient matter to cause a Big Crunch, the expansion of the Universe will continue to no end. bob hi men i wanna become an astronomer but i need the procedures Clozzy Hi, is it possible to know the author and publish date pleas? Thank you . Li Please may I know the author and publish date? Send it to me by email. Thanks! Jaden Can you please give me the name of the author and the date it was published.

Thanks Super novas are AWESOME check out my site for whatisasupernova.blogspot.com For more great picutres! Jewel i really need the author of the information, the date it was published and the publisher. i’d like that information as soon as possible so i don’t fail my chem research paper. please and thank you. Lewis I need to know the author and the date this article was published too. Could you please tell me? Thanks! Tolu Hi, could I please have the author name and the date this article was published please. As I am using some of the infomration on my essay. Please e-mail me the response. Thanks. Audre I wanted to cite a photo on your website for a class project, and I was wondering if you could give me the author and the date this article was published? Thanks a bunch! An Introduction to Supernova Remnants What is a Supernova Remnant? A supernova remnant is simply what is left over (i.e. the remnant) of a supernova. That probably isn't a very helpful definition, so I'll try to explain what I mean.

First, I should probably define what is meant by the term "supernova." A supernova is simply the explosion of a star. Keep in mind, the average star is a million times more massive than the entire Earth, so we're talking about an incredible explosion here. The energy released in a typical supernova is on the order of 1044 joules. (A joule is simply a unit of energy that physicists use). 1044 is a 1 followed by 44 zeroes! There is no comparison for this amount of energy that is even meaningful. Supernovae are so powerful that they can be seen from halfway across the universe (billions of light years!). Here we can draw a comparison. The farthest star you can see with your eye on a dark night is only a few thousand light-years away. I'll need to talk about what causes a supernova, because it is somewhat relevant here. Stars live out their lives by burning (via nuclear fusion reactions) light elements like hydrogen into heavier elements like helium in their core. For a star like the sun, this process will go on for about 10 billion years before it runs out of fuel.

More massive stars have more fuel to burn, but they go through it much more rapidly, so they actually live shorter lives. When a star runs out of hydrogen, it will try to burn helium into even heavier elements, like carbon, nitrogen, and oxygen. If those elements sound familiar, they should. You're a carbon-based lifeform, and you're breathing nitrogen and oxygen as we speak. All of those materials came from the core of some ancient star that exploded and spread its materials around the galaxy, before the Sun and the Earth were even formed! The cartoon on the right shows a deuterium nucleus combining with a tritium nucleus to for an alpha particle (and a stray neutron). Alpha particles are the nuclei of helium atoms, and can be combined with other particles to form all the elements that we commonly see around us. Supernova Types When a star burns all of its available fuel, one of a few things can happen. For a star like our sun, which is only an average sized star, death will be a relatively calm affair. In about 5 billion years, the sun will exhaust its fuel supply, and will puff up into a bloated star called a red giant (swallowing up Earth in the process).

It will then shed it outer layers off into space, forming a beautiful phenomena known as a planetary nebula. At the center of the nebula will be the remains of what was once our sun, a cinder of a star known as a white-dwarf (white because it will be hot, dwarf because it will be very small, about the size of Earth). Planetary nebulae have nothing to do with planets, the name is something of a misnomer. To the left is an example of a planetary nebulae. This one is NGC 6543, which is more commonly known as the "Cat's Eye." These nebulae are the remains of stars that were like our sun that have recently "burned-out." Left by themselves, the planetary nebula will fizzle out after a few million years and the white-dwarf star will continue to smolder for billions of years, before eventually cooling off and being nothing more than a cold hunk of dead star material. However, there is something more exciting that can happen. Many stars in the universe are in binary systems, which is a system of two stars that mutually orbit each other.

If one of these stars turns into a white dwarf, it can actually suck material off of the other star, provided that it is close enough. If a white dwarf gets too massive, it becomes unstable, and can explode if pushed over a certain limit. The resulting explosion is known as a type Ia supernova. The details of the explosion are quite complicated, and are still being worked out by smart people with fancy computers! To the right is an artist's conception of what a binary system containing a white dwarf and a red giant would look like. The white dwarf on the right is pulling material off of the big star on the left, and the material is spiraling in to accrete onto the white dwarf. When the white dwarf pulls off enough matter and reaches a critical mass, it will explode! For stars that are much larger and more massive than the Sun, an entirely different scenario unfolds at the end of their life. First of all, as I mentioned above, massive stars actually live shorter lives than smaller stars. So a star that is 10 or so times more massive than the Sun will live for only a few hundred million years. After it has run through all the fusion reactions it can, it starts to collapse in on itself.

It does this because there are no more reactions going on to provide pressure outward to counteract the force of gravity, which is always pulling it inward. With one final spectacular burst the outer parts of the star bounce off of the core and the resulting shockwave explodes the star, leaving only the core of the star behind, as either a neutron star or a black hole. These are commonly known as core-collapse supernovae, and include type II, type Ib and type Ic supernovae. Both types of supernovae are extraordinarily violent events, releasing more energy in a short amount of time than an entire galaxy (hundreds of billions of stars). You might be wondering if there is any danger to Earth, since this sounds like it could be the plot of a bad Hollywood doomsday movie. Not to worry. A supernova would need to be within a few dozen parsecs of Earth to be dangerous to human life. At this time, there are no stars in that immediate vicinity that are candidates to go supernova anytime soon. There are stars relatively close by in our galaxy that could explode within the next few million years (Eta Carina and Betelgeuse, to name two), but we should be far enough away that we will be protected.

That's not a guarantee, but an educated guess. Supernovae happen at the rate of about once every fifty to one hundred years for a given galaxy. Teams of astronomers using telescopes all over the world scan the skies every night looking for new supernovae. Up until a few years ago, it was relatively rare to find one, but thanks to advances in telescope and computer technology, as well as an increase in the number of people working on it, they are becoming commonplace as billions of galaxies are part of nightly automated surveys. We actually detect supernovae at the rate of more than one per night now! Most of these are far, far away, and require advanced telescopes to see them, but occasionally we'll get one in our own neighborhood. The image on the left is an example of what a distant supernova looks like. The fuzzy green part is the galaxy that the star was located in, and the bright spot is supernova 2006gy, a supernova discovered in 2006. The thing that everyone in the field is waiting for, though, is the next supernova in our own galaxy. We have no idea when it will happen.

We haven't observed one in the Milky Way in over 300 years. If a star should meet its fate in our local section of the galaxy, the show will be spectacular. If it happens within a few thousand light-years of Earth, it will easily be the brightest object in the night sky, perhaps even bright enough to look like a star during the day! It will slowly fade over the next 6 months to a year, at which point it will only be visible through a telescope. What happens next leads us to our discussion of what a supernova remnant is. Supernova Remnants What happens after a star goes supernova? An explosion of that magnitude doesn't simply dissipate in a short amount of time (at least not by human standards). A supernova remnant is simply the expanding blast wave from the explosion plowing through outer space, as well as the remains of what was once the star following behind it. The image to the right is an example of a supernova remnant. It is Cassiopeia A, the last supernova in our galaxy. It is the remnant of a supernova that exploded in the late 17th-century, as seen from Earth. The colors in the image represent different things.

The faint blue ring around the outside is the outer edge of the blast wave running out into space at a speed of about 6000 kilometers per second. It is analogous to the ripple wave created when a rock is dropped into a pond. It shows emission from gas located in the interstellar medium (a fancy term for space) that has been heated up to several million degrees when the blast wave slammed into it. The multiple colors on the inside (green, yellow, orange) show emission from material that was once contained in the star. This is called the ejecta, since it was ejected from the star when it exploded. The fuzzy red color represents emission from interstellar dust that has encountered the blast wave and has been heated up. This image combines images from the three Great Observatories that NASA currently has in operation in outer space: The Hubble Space Telescope (HST), the Chandra X-ray Observatory (CXO), and the Spitzer Space Telescope (SST). These telescopes all see the universe in different wavelengths of light, and all provide valuble pieces of information about what is going on when we examine a supernova remnant.

For more examples (and pictures!) of supernova remnants that come directly from my personal work, see my page on LMC Supernova Remnants . So why do we study supernova remnants? What can possibly be learned by studying the remains of an explosion that has already happened? We are primarily interested with the interaction of the shock wave and the ejecta with the interstellar medium, and how the medium evolves as a result of this interaction. The universe is nearly 14 billion years old, and at this point, every point in a galaxy has most likely been overrun by several supernova blast waves and has been mixed with ejecta from multiple stars. By studying present supernova remnants, we can understand how our local region of space got to be like it is. As I've mentioned above, all "heavy" elements in the universe are made either in stars or in supernova explosions. "Heavy," when referred to by astronomers, means anything heavier than hydrogen or helium. The interaction of the shock wave with interstellar dust is also of interest.

Dust is important in many areas of astrophysics.It is required to form planetary systems and star-forming regions, and its attenuation and extinction effects on starlight can be measured, giving us an idea of how much dust is in the universe. Studying supernova remnants in the infrared (which is how dust grains radiate) can also give us an idea of the amount of dust present. Recent work done by myself and my collaborators has shown a discrepancy between these two methods of determining dust content in the ISM. We don't know exactly why this is yet, but we're working on figuring it out. Perhaps it involves some new physics that we haven't considered yet, perhaps it is just a consequence of using rather indirect methods to come up with a measurement. Stars | Science Mission Directorate Science Mission Directorate Exoplanets Stars Stars are the most widely recognized astronomical objects, and represent the most fundamental building blocks of galaxies. The age, distribution, and composition of the stars in a galaxy trace the history, dynamics, and evolution of that galaxy. Moreover, stars are responsible for the manufacture and distribution of heavy elements such as carbon, nitrogen, and oxygen, and their characteristics are intimately tied to the characteristics of the planetary systems that may coalesce about them.

Consequently, the study of the birth, life, and death of stars is central to the field of astronomy. Star Formation Stars are born within the clouds of dust and scattered throughout most galaxies. A familiar example of such as a dust cloud is the Orion Nebula. Turbulence deep within these clouds gives rise to knots with sufficient mass that the gas and dust can begin to collapse under its own gravitational attraction. As the cloud collapses, the material at the center begins to heat up. Known as a protostar, it is this hot core at the heart of the collapsing cloud that will one day become a star. Three-dimensional computer models of star formation predict that the spinning clouds of collapsing gas and dust may break up into two or three blobs; this would explain why the majority the stars in the Milky Way are paired or in groups of multiple stars. The observations of Eta Carinae's light echo are providing new insight into the behavior of powerful massive stars on the brink of detonation. Credit: NOAO, AURA, NSF, and N. Smith (University of Arizona) As the cloud collapses, a dense, hot core forms and begins gathering dust and gas.

Not all of this material ends up as part of a star — the remaining dust can become planets, asteroids, or comets or may remain as dust. In some cases, the cloud may not collapse at a steady pace. In January 2004, an amateur astronomer, James McNeil, discovered a small nebula that appeared unexpectedly near the nebula Messier 78, in the constellation of Orion. When observers around the world pointed their instruments at McNeil's Nebula , they found something interesting — its brightness appears to vary. Observations with NASA's Chandra X-ray Observatory provided a likely explanation: the interaction between the young star's magnetic field and the surrounding gas causes episodic increases in brightness. Main Sequence Stars A star the size of our Sun requires about 50 million years to mature from the beginning of the collapse to adulthood. Our Sun will stay in this mature phase (on the main sequence as shown in the Hertzsprung-Russell Diagram) for approximately 10 billion years. Stars are fueled by the nuclear fusion of hydrogen to form helium deep in their interiors.

The outflow of energy from the central regions of the star provides the pressure necessary to keep the star from collapsing under its own weight, and the energy by which it shines. As shown in the Hertzsprung-Russell Diagram, Main Sequence stars span a wide range of luminosities and colors, and can be classified according to those characteristics. The smallest stars, known as red dwarfs, may contain as little as 10% the mass of the Sun and emit only 0.01% as much energy, glowing feebly at temperatures between 3000-4000K. Despite their diminutive nature, red dwarfs are by far the most numerous stars in the Universe and have lifespans of tens of billions of years. On the other hand, the most massive stars, known as hypergiants, may be 100 or more times more massive than the Sun, and have surface temperatures of more than 30,000 K. Hypergiants emit hundreds of thousands of times more energy than the Sun, but have lifetimes of only a few million years.

Although extreme stars such as these are believed to have been common in the early Universe, today they are extremely rare - the entire Milky Way galaxy contains only a handful of hypergiants. Stars and Their Fates In general, the larger a star, the shorter its life, although all but the most massive stars live for billions of years. When a star has fused all the hydrogen in its core, nuclear reactions cease. Deprived of the energy production needed to support it, the core begins to collapse into itself and becomes much hotter. Hydrogen is still available outside the core, so hydrogen fusion continues in a shell surrounding the core. The increasingly hot core also pushes the outer layers of the star outward, causing them to expand and cool, transforming the star into a red giant. If the star is sufficiently massive, the collapsing core may become hot enough to support more exotic nuclear reactions that consume helium and produce a variety of heavier elements up to iron. However, such reactions offer only a temporary reprieve. Gradually, the star's internal nuclear fires become increasingly unstable - sometimes burning furiously, other times dying down. These variations cause the star to pulsate and throw off its outer layers, enshrouding itself in a cocoon of gas and dust.

What happens next depends on the size of the core. Average Stars Become White Dwarfs For average stars like the Sun, the process of ejecting its outer layers continues until the stellar core is exposed. This dead, but still ferociously hot stellar cinder is called a White Dwarf . White dwarfs, which are roughly the size of our Earth despite containing the mass of a star, once puzzled astronomers - why didn't they collapse further? What force supported the mass of the core? Quantum mechanics provided the explanation. Pressure from fast moving electrons keeps these stars from collapsing. The more massive the core, the denser the white dwarf that is formed. Thus, the smaller a white dwarf is in diameter, the larger it is in mass! These paradoxical stars are very common - our own Sun will be a white dwarf billions of years from now. White dwarfs are intrinsically very faint because they are so small and, lacking a source of energy production, they fade into oblivion as they gradually cool down. This fate awaits only those stars with a mass up to about 1.4 times the mass of our Sun. Above that mass, electron pressure cannot support the core against further collapse. Such stars suffer a different fate as described below.

White Dwarfs May Become Novae If a white dwarf forms in a binary or multiple star system, it may experience a more eventful demise as a nova. Nova is Latin for "new" - novae were once thought to be new stars. Today, we understand that they are in fact, very old stars - white dwarfs. If a white dwarf is close enough to a companion star, its gravity may drag matter - mostly hydrogen - from the outer layers of that star onto itself, building up its surface layer. When enough hydrogen has accumulated on the surface, a burst of nuclear fusion occurs, causing the white dwarf to brighten substantially and expel the remaining material. Within a few days, the glow subsides and the cycle starts again. Sometimes, particularly massive white dwarfs (those near the 1.4 solar mass limit mentioned above) may accrete so much mass in the manner that they collapse and explode completely, becoming what is known as a supernova. Supernovae Leave Behind Neutron Stars or Black Holes Main sequence stars over eight solar masses are destined to die in a titanic explosion called a supernova . A supernova is not merely a bigger nova. In a nova, only the star's surface explodes.

In a supernova, the star's core collapses and then explodes. In massive stars, a complex series of nuclear reactions leads to the production of iron in the core. Having achieved iron, the star has wrung all the energy it can out of nuclear fusion - fusion reactions that form elements heavier than iron actually consume energy rather than produce it. The star no longer has any way to support its own mass, and the iron core collapses. In just a matter of seconds the core shrinks from roughly 5000 miles across to just a dozen, and the temperature spikes 100 billion degrees or more. The outer layers of the star initially begin to collapse along with the core, but rebound with the enormous release of energy and are thrown violently outward. Supernovae release an almost unimaginable amount of energy. For a period of days to weeks, a supernova may outshine an entire galaxy. Likewise, all the naturally occurring elements and a rich array of subatomic particles are produced in these explosions. On average, a supernova explosion occurs about once every hundred years in the typical galaxy.

About 25 to 50 supernovae are discovered each year in other galaxies, but most are too far away to be seen without a telescope. Neutron Stars If the collapsing stellar core at the center of a supernova contains between about 1.4 and 3 solar masses, the collapse continues until electrons and protons combine to form neutrons, producing a neutron star . Neutron stars are incredibly dense - similar to the density of an atomic nucleus. Because it contains so much mass packed into such a small volume, the gravitation at the surface of a neutron star is immense. Like the White Dwarf stars above, if a neutron star forms in a multiple star system it can accrete gas by stripping it off any nearby companions. The Rossi X-Ray Timing Explorer has captured telltale X-Ray emissions of gas swirling just a few miles from the surface of a neutron star. Neutron stars also have powerful magnetic fields which can accelerate atomic particles around its magnetic poles producing powerful beams of radiation. Those beams sweep around like massive searchlight beams as the star rotates. If such a beam is oriented so that it periodically points toward the Earth, we observe it as regular pulses of radiation that occur whenever the magnetic pole sweeps past the line of sight.

In this case, the neutron star is known as a pulsar. Black Holes If the collapsed stellar core is larger than three solar masses, it collapses completely to form a black hole: an infinitely dense object whose gravity is so strong that nothing can escape its immediate proximity, not even light. Since photons are what our instruments are designed to see, black holes can only be detected indirectly. Indirect observations are possible because the gravitational field of a black hole is so powerful that any nearby material - often the outer layers of a companion star - is caught up and dragged in. As matter spirals into a black hole, it forms a disk that is heated to enormous temperatures, emitting copious quantities of X-rays and Gamma-rays that indicate the presence of the underlying hidden companion. From the Remains, New Stars Arise The dust and debris left behind by novae and supernovae eventually blend with the surrounding interstellar gas and dust, enriching it with the heavy elements and chemical compounds produced during stellar death. Eventually, those materials are recycled, providing the building blocks for a new generation of stars and accompanying planetary systems. Supernovas, Supernovae Information, Exploding Star Facts, News, Photos -- National Geographic Space Photograph courtesy J. J.

Hester (Arizona State University)/NASA Some stars behave as if it's better to burn out than to fade away. These stars end their evolutions in massive cosmic explosions known as supernovae. When supernovae explode they jettison matter into space at some 9,000 to 25,000 miles (15,000 to 40,000 kilometers) per second. These blasts produce much of the material in the universe—including some elements, like iron, which make up our planet and even ourselves. Heavy elements are only produced in supernovae, so all of us carry the remnants of these distant explosions within our own bodies. Supernovae add enriching elements to space clouds of dust and gas, further interstellar diversity, and produce a shock wave that compresses clouds of gas to aid new star formation. But only a select few stars become supernovae. Many stars cool in later life to end their days as white dwarfs and, later, black dwarfs. Star Fusion But massive stars, many times larger than our own sun, may create a supernova when their core's fusion process runs out of fuel.

Star fusion provides a constant outward pressure, which exists in balance with the star's own mass-driven, inward gravitational pull. When fusion slows, outbound pressure drops and the star's core begins to condense under gravity—becoming ever denser and hotter. To outward appearances, such stars begin growing, swelling into bodies known as red supergiants. But at their cores shrinking continues, making a supernova imminent. When a star's core contracts to a critical point a series of nuclear reactions is unleashed. This fusion staves off core collapse for a time—but only until the core is composed largely of iron, which can no longer sustain star fusion. In a microsecond, the core may reach temperatures of billions of degrees Celsius. Iron atoms become crushed so closely together that the repulsive forces of their nuclei create a recoil of the squeezed core—a bounce that causes the star to explode as a supernova and give birth to an enormous, superheated, shock wave. White Dwarfs Supernovae also occur in binary star systems. Smaller stars, up to eight times the mass of our own sun, typically evolve into white dwarves.

A star condensed to this size, about that of Earth, is very dense and thus has strong enough gravitational pull to gather material from the system's second star if it is close enough. If a white dwarf takes on enough mass it reaches a level called the Chandrasekhar Limit. At this point the pressure at its center will become so great that runaway fusion occurs and the star detonates in a thermonuclear supernova. A supernova can light the sky up for weeks, and the massive transfer of matter and energy leaves behind a very different star. Typically only a tiny core of neutrons, a spinning neutron star, is left to evidence a supernova. Neutron stars give off radio waves in a steady stream or, as pulsars, in intermittent bursts. If a star was so massive (at least ten times the size of our sun) that it leaves behind a large core, a new phenomenon will occur. Because such a burned-out core has no energy source to fuse, and thus produces no outward pressure, it may become engulfed by its own gravity and turn into a cosmic sinkhole for energy and matter—a black hole.

Black Holes | Science Mission Directorate Science Mission Directorate Exoplanets Black Holes Don't let the name fool you: a black hole is anything but empty space. Rather, it is a great amount of matter packed into a very small area - think of a star ten times more massive than the Sun squeezed into a sphere approximately the diameter of New York City. The result is a gravitational field so strong that nothing, not even light, can escape. In recent years, NASA instruments have painted a new picture of these strange objects that are, to many, the most fascinating objects in space. Intense X-ray flares thought to be caused by a black hole devouring a star. (Video) Watch the Video Although the term was not coined until 1967 by Princeton physicist John Wheeler, the idea of an object in space so massive and dense that light could not escape it has been around for centuries. Most famously, black holes were predicted by Einstein's theory of general relativity, which showed that when a massive star dies, it leaves behind a small, dense remnant core. If the core's mass is more than about three times the mass of the Sun, the equations showed, the force of gravity overwhelms all other forces and produces a black hole.

A video about black holes. Watch the video Scientists can't directly observe black holes with telescopes that detect x-rays, light, or other forms of electromagnetic radiation. We can, however, infer the presence of black holes and study them by detecting their effect on other matter nearby. If a black hole passes through a cloud of interstellar matter, for example, it will draw matter inward in a process known as accretion. A similar process can occur if a normal star passes close to a black hole. In this case, the black hole can tear the star apart as it pulls it toward itself. As the attracted matter accelerates and heats up, it emits x-rays that radiate into space. Recent discoveries offer some tantalizing evidence that black holes have a dramatic influence on the neighborhoods around them - emitting powerful gamma ray bursts, devouring nearby stars, and spurring the growth of new stars in some areas while stalling it in others. One Star's End is a Black Hole's Beginning Most black holes form from the remnants of a large star that dies in a supernova explosion.

(Smaller stars become dense neutron stars, which are not massive enough to trap light.) If the total mass of the star is large enough (about three times the mass of the Sun), it can be proven theoretically that no force can keep the star from collapsing under the influence of gravity. However, as the star collapses, a strange thing occurs. As the surface of the star nears an imaginary surface called the "event horizon," time on the star slows relative to the time kept by observers far away. When the surface reaches the event horizon, time stands still, and the star can collapse no more - it is a frozen collapsing object. Astronomers have identified a candidate for the smallest-known black hole. (Video) Watch the Video Even bigger black holes can result from stellar collisions. Soon after its launch in December 2004, NASA's Swift telescope observed the powerful, fleeting flashes of light known as gamma ray bursts. Chandra and NASA's Hubble Space Telescope later collected data from the event's "afterglow," and together the observations led astronomers to conclude that the powerful explosions can result when a black hole and a neutron star collide, producing another black hole.

Babies and Giants Although the basic formation process is understood, one perennial mystery in the science of black holes is that they appear to exist on two radically different size scales. On the one end, there are the countless black holes that are the remnants of massive stars. Peppered throughout the Universe, these "stellar mass" black holes are generally 10 to 24 times as massive as the Sun. Astronomers spot them when another star draws near enough for some of the matter surrounding it to be snared by the black hole's gravity, churning out x-rays in the process. Most stellar black holes, however, lead isolated lives and are impossible to detect. Judging from the number of stars large enough to produce such black holes, however, scientists estimate that there are as many as ten million to a billion such black holes in the Milky Way alone. On the other end of the size spectrum are the giants known as "supermassive" black holes, which are millions, if not billions, of times as massive as the Sun. Astronomers believe that supermassive black holes lie at the center of virtually all large galaxies, even our own Milky Way.

Astronomers can detect them by watching for their effects on nearby stars and gas. This chart shows the relative masses of super-dense cosmic objects. Read the full article Historically, astronomers have long believed that no mid-sized black holes exist. However, recent evidence from Chandra, XMM-Newton and Hubble strengthens the case that mid-size black holes do exist. One possible mechanism for the formation of supermassive black holes involves a chain reaction of collisions of stars in compact star clusters that results in the buildup of extremely massive stars, which then collapse to form intermediate-mass black holes. The star clusters then sink to the center of the galaxy, where the intermediate-mass black holes merge to form a supermassive black hole. Neutron Stars: Definition & Facts Neutron Stars: Definition & Facts By Nola Taylor Redd, Space.com Contributor | July 31, 2013 01:26am ET MORE Neutron stars are created when giant stars die in supernovas and their cores collapse, with the protons and electrons essentially melting into each other to form neutrons. Credit: NASA/Dana Berry Neutron stars are city-size stellar objects with a mass about 1.4 times that of the sun.

Born from the explosive death of another, larger stars, these tiny objects pack quite a punch. Let's take a look at what they are, how they form, and how they vary. A stellar phoenix When stars four to eight times as massive as the sun explode in a violent supernova, their outer layers can blow off in an often-spectacular display, leaving behind a small, dense core that continues to collapse. Gravity presses the material in on itself so tightly that protons and electrons combine to make neutrons, yielding the name "neutron star." [Supernova Photos: Great Images of Star Explosions] Neutron stars pack their mass inside a 20-kilometer (12.4 miles) diameter. They are so dense that a single teaspoon would weigh a billion tons — assuming you somehow managed to snag a sample without being captured by the body's strong gravitational pull. On average, gravity on a neutron star is 2 billion times stronger than gravity on Earth. In fact, it's strong enough to significantly bend radiation from the star in a process known as gravitational lensing, allowing astronomers to see some of the back side of the star.

The power from the supernova that birthed it gives the star an extremely quick rotation, causing it to spin several times in a second. Neutron stars can spin as fast as 43,000 times per minute , gradually slowing over time. Though they look serene and silent from our vantage on Earth, stars are actually roiling balls of violent plasma. Test your stellar smarts with this quiz. 0 of 10 questions complete Star Quiz: Test Your Stellar Smarts Though they look serene and silent from our vantage on Earth, stars are actually roiling balls of violent plasma. Test your stellar smarts with this quiz. 0 of Start Over | More Quizzes If a neutron star is part of a binary system that survived the deadly blast from its supernova (or if it captured a passing companion), things can get even more interesting. If the second star is less massive than the sun, it pulls mass from its companion into a Roche lobe, a balloon-like cloud of material that orbits the neutron star. Companion stars up to 10 times the sun's mass create similar mass transfers that are more unstable and don't last as long.

Stars more than 10 times as massive as the sun transfer material in the form of stellar wind. The material flows along the magnetic poles of the neutron star, creating X-ray pulsations as it is heated. By 2010, approximately 1,800 pulsars had been identified through radio detection, with another 70 found by gamma-rays. Some pulsars even have planets orbiting them — and some turn into planets . Types of neutron stars Some neutron stars have jets of materials streaming out of them at nearly the speed of light. As these beams pan past Earth, they flash like the bulb of a lighthouse . This pulsing appearance led them to be called pulsars. When X-ray pulsars capture the material flowing from more massive companions, that material interacts with the magnetic field to produce high-powered beams that can be seen in the radio, optical, X-ray or gamma-ray spectrum. Because their main power source comes from the material from their companion, they are often called "accretion-powered pulsars." "Spin-powered pulsars" are driven by the stars rotation, as high-energy electrons interact with the pulsar's magnetic field above their poles.

Young neutron stars before they cool can also produce pulses of X-rays when some parts are hotter than others. As material within a pulsar accelerates within the magnetosphere of a pulsar, the neutron star produces gamma-ray emission. The transfer of energy in these gamma-ray pulsars slows the spin of the star. Magnetars have magnetic fields a thousand times stronger than the average neutron star. The resulting drag causes the star to take longer to rotate. Author Bio Nola Taylor Redd, Space.com Contributor Nola Taylor Redd is a contributing writer for Space.com. She loves all things space and astronomy-related, and enjoys the opportunity to learn more. She has a Bachelor’s degree in English and Astrophysics from Agnes Scott college and served as an intern at Sky & Telescope magazine. In her free time, she homeschools her four children.

Follow her on Twitter at @NolaTRedd Nola Taylor Redd, Space.com Contributor on Latest on Neutron Stars: Definition & Facts Supernova 1987A Decoded | holoscience.com | The Electric Universe Supernova 1987A Decoded Posted on August 24, 2005 by Wal Thornhill Supernova 1987A is the closest supernova event since the invention of the telescope. It was first seen in February 1987 in the nearby Magellanic cloud, a dwarf companion galaxy of the Milky Way, and only 169,000 light years from Earth. Close observation since 1987 has now provided proof that supernovae are catastrophic electrical discharges focused on a star. The enigmatic and beautiful structure of SN1987A with its three axial rings. The brightening of the equatorial ring is obvious. The two bright stars are just in the field of view and are not associated with the supernova. Credit: NASA/STScI/CfA/P.Challis. A supernova is one of the most energetic events witnessed in the universe.

The accepted explanation is that it occurs at the end of a star’s lifetime, or red giant stage, when the star’s nuclear fuel is exhausted. There is no more release of nuclear energy in the core so the huge star collapses in on itself. If sufficiently massive, the imploding layers of the star are thought to “rebound” when they hit the core, resulting in an explosion, and the blast wave ejects the star’s envelope into interstellar space. The bright equatorial ring is caused by the collision of exploded matter from the star with the remnants of an earlier stellar “wind.” The two faint rings are a problem. The best that theorists have been able to manage is to postulate some kind of rotating beam from an assumed supernova remnant, sweeping and lighting up a shell of gas expelled at an earlier epoch. The ad hoc nature of these explanations is obvious. The detection of a pulsar remnant after some supernovae is explained by the implosion of the stellar core to produce a neutron star. Pulsars emit bursts of radiation up to thousands of times a second.

It is believed that a pulsar must be a super-collapsed stellar object that can spin up to thousands of times a second and emit a rotating beam of X-rays (like a lighthouse). Commonsense suggests that this mechanical model is wrong when some pulsars rev beyond the redline, even for such a bizarre object. A recent example of conventional thinking can be seen on the Chandra website. On August 17, a news story was posted: Supernova 1987A: Fast Forward to the Past. Credit: X-ray: NASA/CXC/PSU/S.Park & D.Burrows.; Optical: NASA/STScI/CfA/P.Challis Recent Chandra observations have revealed new details about the fiery ring surrounding the stellar explosion that produced Supernova 1987A. The data give insight into the behavior of the doomed star in the years before it exploded, and indicate that the predicted spectacular brightening of the circumstellar ring has begun.. The site of the explosion was traced to the location of a blue supergiant star called Sanduleak-69º 202 (SK-69 for short) that had a mass estimated at approximately 20 Suns.

Subsequent optical, ultraviolet and X-ray observations have enabled astronomers to piece together the following scenario for SK-69: about ten million years ago the star formed out of a dark, dense, cloud of dust and gas; roughly a million years ago, the star lost most of its outer layers in a slowly moving stellar wind that formed a vast cloud of gas around it; before the star exploded, a high-speed wind blowing off its hot surface carved out a cavity in the cool gas cloud. The intense flash of ultraviolet light from the supernova illuminated the edge of this cavity to produce the bright ring seen by the Hubble Space Telescope. In the meantime the supernova explosion sent a shock wave rumbling through the cavity. In 1999, Chandra imaged this shock wave, and astronomers have waited expectantly for the shock wave to hit the edge of the cavity, where it would encounter the much denser gas deposited by the red supergiant wind, and produce a dramatic increase in X-radiation. The latest data from Chandra and the Hubble Space Telescope indicate that this much-anticipated event has begun. Optical hot-spots now encircle the ring like a necklace of incandescent diamonds.

The Chandra image reveals multimillion-degree gas at the location of the optical hot-spots. X-ray spectra obtained with Chandra provide evidence that the optical hot-spots and the X-ray producing gas are due to a collision of the outward-moving supernova shock wave with dense fingers of cool gas protruding inward from the circumstellar ring. Illustration: NASA/CXC/M.Weiss These fingers were produced long ago by the interaction of the high-speed wind with the dense circumstellar cloud. The collision of the outward-moving supernova shock wave (yellow) with the dense fingers of cool gas produce bright spots (white) of optical and X-ray emission. The expanding debris (blue) of the exploded star lags behind the shock wave and, except for a thin shell around the outer edge (gold), is too cool to produce X-rays. The dense fingers and the visible circumstellar ring represent only the inner edge of a much greater, unknown amount of matter ejected long ago by SK-69. As the shock wave moves into the dense cloud, ultraviolet and X-radiation from the shock wave will heat much more of the circumstellar gas.

Then, as remarked by Richard McCray, one of the scientists involved in the Chandra research, “Supernova 1987A will be illuminating its own past.” On the contrary, Supernova 1987A illuminates only how poorly the theory of supernova explosions fits the observations. The official explanatory illustration above is conjectural and relies (again) on invisible matter that the star is supposed to have conveniently pre-released in just the right places and filamentary form to produce the observed effects. To say, “the predicted spectacular brightening of the circumstellar ring” is disingenuous. Neither the presence of the three rings nor the pattern of bright “beads” in the equatorial ring was predicted from theory. “The Hubble images of the rings are quite spectacular and unexpected,” said Dr. Chris Burrows of the European Space Agency and the Space Telescope Science Institute in Baltimore, Maryland, when first discovered. “This is an unprecedented and bizarre object. We have never seen anything behave like this before.” The pattern of brightening is not explained by an expanding shock front. There is a more fundamental problem with SN1987A.

The star at the center was found to have been a “blue supergiant.” But a supernova explosion is thought to require a ten-times bigger red supergiant star. There is no evidence that SK-69 was a red supergiant star, emitting a massive stellar wind. The history of the star is not based on observation, it is a fabrication required by the theory. The axial shape of SN1987A is that of a planetary nebula. Fifty years ago a British scientist, Dr. Charles E. R. Bruce (1902-1979), argued that the bipolar shape, temperatures and magnetic fields of planetary nebulae could be explained as an electrical discharge. Bruce was ideally situated to make the discovery, being both an electrical engineer versed in high-energy lightning behavior and a Fellow of the Royal Astronomical Society. He was ignored. C. E. R. Bruce indicating examples of planetary nebulae which are clearly not simply expanding shells around a central star. Courtesy of E. Crew. The place to look for real answers is not in abstract astrophysical theory but in the practical experiments and supercomputer simulations of some plasma cosmologists.

They unleash the most powerful man-made electrical discharges on this planet. The result is called the “z-pinch.” The term “z-pinch” comes from the usual representation of a current flowing along the z-axis, parallel to the magnetic field. With a strong enough current, the plasma formed by the discharge electromagnetically “pinches” into a string of sausages, donuts and plasma instabilities, along the z-axis. Electrical discharges (Lichtenberg figures) illuminate the surface of the Z machine, the world's most powerful X-ray source, during a recent accelerator shot. The most recent advance gave an X-ray power of about 290 trillion watts for billionths of a second, about 80 times the entire world's output of electricity. Since Bruce, and following the pioneering work of Hannes Alfven on an electric circuit model of stars, it has become clear to plasma cosmologists that the electrical z-pinch effect is instrumental in forming stars. Once formed, stars continue to be lit by electrical power delivered throughout the universe by cosmic transmission lines known as Birkeland current filaments. These giant filaments can be traced by their radio transmissions.

Stars also trace the Birkeland currents in galaxies in the same way that electric streetlights trace the routes of electrical cables. Stars are an electrical, not a thermonuclear, phenomenon. Consequently, a star’s size, color and spectrum tell us nothing about its age. A red supergiant star is huge because it is under low electrical stress. It is not at the end of its life. And being under low stress it is not expected to explode. However, a blue star is under extreme electrical stress. We do not have to advance the ad hoc postulate that SN1987A was a red supergiant before it exploded. Here we see the changes in the equatorial ring over time. Some astronomers wrote, "The origin of the circumstellar ring is the outstanding mystery of SN 1987A. Why is the ring so thin, and so nearly circular? Why is it expanding so slowly? Today we have no clear answers to these questions. But we do know that the ring around SN1987A is not unique. Many planetary nebulae have remarkably similar bipolar structures." How does a star explode? The conventional “implosion followed by explosion” model has many shortcomings.

An electric star, on the other hand, has internal charge separation which can power a star-wide, expulsive lightning-flash. The star relieves electrical stress by fissioning or blowing off charged matter. A star also has electromagnetic energy stored in an equatorial current ring. Matter is ejected equatorially by discharges between the current ring and the star. Our own Sun does it regularly on a small scale. However, if the stored energy reaches some critical value it may be released in the form of a bipolar discharge, or ejection of matter, along the rotational axis. The remnant of SN 1987A shows such a bipolar ejection in the form of two blobs of matter (inside the bright ring). A companion star may initiate a stellar discharge that results in fissioning. It is significant in this context that an unexplained and much-disputed “Mystery Spot” appeared along the line joining the two blobs and was seen briefly a couple of months after the explosion and then quickly faded from sight. The spot was too far away to have been ejected by the supernova and its brightness (10% of the supernova) was too great to be explained by reflection off a cloud of matter.

It may have been a faint companion that triggered, or was a part of the circuit of the electrical supernova discharge. The bright beaded ring shows that matter has been ejected equatorially. However, the ring is not expanding. The other two fainter rings are also arranged above and below the star on the same axis and show similar but fainter “bright spots”. Conventionally, a shock wave from an exploding star should show spherical, rather than axial, symmetry. And there is no particular reason why the shock front should form a ring of bright spots. We should expect some visible indication of the spherical cavity. Stars are an electrical plasma discharge phenomenon. Electrical energy produces heavy elements near the surface of all stars. The energy is transferred over cosmic distances via Birkeland current transmission lines. The energy may be released gradually or stored in a stellar circuit and unleashed catastrophically. It is these cosmic circuits that are the energy source for the supernova explosion – not the star. That is why the energy output of some nebulae exceeds that available from the central star. See Shocks from Eta Carina .

The electrical energy released in supernova fissioning is prodigious, so it is no surprise that there is an abundance of heavy elements and neutrinos dispersed into space by the stellar “lightning flash.” The crucial evidence for the electrical nature of supernovae must come from experiment and observation. Anthony L. Peratt, Fellow, IEEE, published a seminal paper in the IEEE Transactions on Plasma Science, Vol. 31, No. 6, December 2003. It was titled “ Characteristics for the Occurrence of a High-Current, Z-Pinch Aurora as Recorded in Antiquity .” In it he explained the unusual characteristics of a high-energy plasma discharge. He discussed mega-ampere particle beams and showed their characteristic 56- and 28-fold symmetry. He wrote: “A solid beam of charged particles tends to form hollow cylinders that may then filament into individual currents.

When observed from below, the pattern consists of circles, circular rings of bright spots, and intense electrical discharge streamers connecting the inner structure to the outer structure.“ This photograph shows a 0.6-mm-thick titanium witness plate that has been placed 15 cm in front of a 100 kilo-Gauss, sub-megaampere charged particle beam. Initially, the particle beam was cylindrical but after traveling the 15 cm has filamented. In the sub-gigaampere range, the maximum number of self-pinched filaments allowed before the cylindrical magnetic field will no longer split into "islands" for the parameters above has been found to be 56. These results verify that individual current filaments were maintained by their azimuthal self-magnetic fields, a property lost by increasing the number of electrical current filaments.

The scaling is constant for a given hollow beam thickness, from microampere beams to multi-megaampere beams and beam diameters of millimeters to thousands of kilometers. This scaling of plasma phenomena has been extended to more than 14 orders of magnitude, so the bright ring of supernova 1987A can be considered as a stellar scale “witness plate” with the equatorial ejecta sheet acting as the “plate” for the otherwise invisible axial Birkeland currents. Peratt adds: “Because the electrical current-carrying filaments are parallel, they attract via the Biot-Savart force law, in pairs but sometimes three. This reduces the 56 filaments over time to 28 filaments, hence the 56 and 28 fold symmetry patterns. In actuality, during the pairing, any number of filaments less than 56 may be recorded as pairing is not synchronized to occur uniformly. However, there are ‘temporarily stable’ (longer state durations) at 42, 35, 28, 14, 7, and 4 filaments.

Each pair formation is a vortex that becomes increasingly complex.” The images of SN 1987A shows the Birkeland currents around the star have paired to a number close to 28. The bright spots show a tendency toward pairing and groups of three. This witness plate model explains why the glowing ring is so nearly circular and is expanding very slowly – unlike a shock front. It is more like a cloud at night moving through the beams of a ring of searchlights. If the equatorial ring shows the Birkeland currents in the outer sheath of an axial plasma current column, then the supernova outburst is the result of a cosmic z-pinch in the central column, focused on the central star. It is important to note that the z-pinch naturally takes the ubiquitous hourglass shape of planetary nebulae. No special conditions and mysteriously conjured magnetic fields are required. Experimental and simulation derived geometries for extreme plasma currents in a plasma column. The Birkeland currents will only be visible where the plasma density is high. It is also the shape of SN1987A with its three rings.

It will be instructive for plasma cosmologists to watch closely the development of SN1987A’s “necklace of incandescent diamonds.” I do not expect the ring to grow as a shock-wave-produced ring would be expected to. Some bright spots may be seen to rotate about each other and to merge. It is an opportunity more rare and valuable than a diamond to be able to verify the electric discharge nature of a supernova. Supernova 1987A will be illuminating the future of plasma cosmology! White Dwarfs: Compact Corpses of Stars White Dwarfs: Compact Corpses of Stars By Nola Taylor Redd, Space.com Contributor | November 26, 2013 06:11pm ET MORE NASA's Hubble Space Telescope captures a field of stellar husks. These ancient white dwarfs are 12 to 13 billion years old, only slightly younger than the universe itself. In theory, white dwarfs will eventually stop emitting light and heat and become black dwarfs. Credit: NASA and H. Richer (University of British Columbia).

The stars in the sky may seem ageless and unchanging, but eventually most of them will turn into white dwarfs, the last observable stage of evolution for low- and medium-mass stars. These dim stellar corpses dot the galaxy, leftovers from brightly burning stars. Formation Main-sequence stars form from clouds of dust and gas drawn together by gravity. How the stars evolve through their lifetime depends on their mass. The most massive stars, with eight times the mass of the sun or more, will never become white dwarfs. Instead, at the end of their lives, they will explode in a violent supernova , leaving behind a neutron star or black hole . Smaller stars, however, will take a slightly more sedate path. Low- to medium-mass stars, such as the sun , will eventually swell up into red giants , eventually shedding their outer layers into a ring known as a planetary nebula (early observers thought the nebulae resembled planets such as Neptune and Uranus). The core that is left behind will be a white dwarf, a husk of a star in which no hydrogen fusion occurs. Smaller stars, such as red dwarfs, don't make it to the red giant state.

They simply burn through all of the hydrogen within the star, leaving behind the shell that is a white dwarf. However, red dwarfs take trillions of years to consume their fuel, far longer than the 13.8-billion-year-old age of the universe, so no red dwarfs have yet become white dwarfs. Characteristics When a star runs out of fuel, it collapses inward on itself. White dwarfs contain approximately the mass of the sun but have roughly the radius of Earth. This makes them incredibly dense, beaten out only by neutron stars and black holes. The gravity on the surface of a white dwarf is 350,000 times that of gravity on Earth. White dwarfs reach this incredible density because they are so collapsed that their electrons are smashed together, forming what is called "degenerate matter." This means that a more massive white dwarf has a smaller radius than its less massive counterpart. Burning stars balance the inward push of gravity with the outward push from fusion, but in a white dwarf, electrons must squeeze tightly together to create that outward-pressing force. As such, having shed much of its mass during the red giant phase, no white dwarf can exceed 1.4 times the mass of the sun.

This image is NGC 6543 known as the Cat's Eye Nebula as it appears to the Chandra X-Ray Observatory and Hubble Telescope. A planetary nebula is a phase of stellar evolution that the sun should experience several billion years from now, when it expands to become a red giant and then sheds most of its outer layers, leaving behind a hot core that contracts to form a dense white dwarf star. This image was released Oct. 10, 2012. Credit: X-ray: NASA/CXC/RIT/J.Kastner et al.; Optical: NASA/STScI One last kick While many white dwarfs fade away into relative obscurity, eventually radiating away all of their energy and becoming a black dwarf, those that have companions may suffer a different fate. If the white dwarf is part of a binary system, it may be able to pull material from its companion onto its surface. Increasing the mass can have some interesting results. [ VIDEO: Cannibal White Dwarf Feeds on Companion Star ] One possibility is that adding more mass to the white dwarf could cause it to collapse into a much denser neutron star. A far more explosive result is the Type 1a supernova .

As the white dwarf pulls material from a companion star, the temperature increases, eventually triggering a runaway reaction that detonates in a violent supernova that destroys the white dwarf. This process is known as a single-degenerate model of a Type 1a supernova. If the companion is another white dwarf instead of an active star, the two stellar corpses merge together to kick off the fireworks. This process is known as a double-degenerate model of a Type 1a supernova. At other times, the white dwarf may pull just enough material from its companion to briefly ignite in a nova, a far smaller explosion. Because the white dwarf remains intact, it can repeat the process several times when it reaches the critical point, briefly breathing life back into the dying star over and over again. Author Bio Nola Taylor Redd, Space.com Contributor Nola Taylor Redd is a contributing writer for Space.com. She loves all things space and astronomy-related, and enjoys the opportunity to learn more. She has a Bachelor’s degree in English and Astrophysics from Agnes Scott college and served as an intern at Sky & Telescope magazine. In her free time, she homeschools her four children.

Follow her on Twitter at @NolaTRedd Nola Taylor Redd, Space.com Contributor on Latest on White Dwarfs: Compact Corpses of Stars

Question: What is the name given to the super dense stars that sometimes result form a supernova?
Answer: Neutron Stars